#include <bits/stdc++.h>
#define pii pair<int,int>
#define fst first
#define snd second
#define getchar_unlocked getchar
using namespace std;
stack<pii> s;
int n,a,b;
inline int readInt() {
int x = 0;
char ch = getchar_unlocked();
while (ch < '0' || ch > '9') ch = getchar_unlocked();
while (ch >= '0' && ch <= '9'){
x = (x << 3) + (x << 1) + ch - '0';
ch = getchar_unlocked();
}
return x;
}
int main()
{
n = readInt();
for (int i=0;i<n;i++)
{
a = readInt();
b = readInt();
if (s.empty()) {s.push({a,b});}
else
{
if (a - s.top().fst > s.top().snd - b)
{
while (s.size())
{
if (a - s.top().fst <= b - s.top().snd) {s.pop();}
else {break;}
}
s.push({a,b});
}
}
//cout<<i<<" "<<s.size()<<"\n";
}
printf("%d\n",(int)s.size());
return 0;
}
